When containers have to be emptied the methods adopted depend to a large extent on the contents of the container. In the case of flowable non-liquid material, such as granules, gravitational discharge is the preferred option. To facilitate this form of discharge attempts have been made to develop containers which have a bottom discharge means. For a number of reasons containers with a bottom discharge incorporated in a base or pallet forming part of the container has not found favour with users.
An alternative is to tilt the container, usually in a tilting device on which the container is mounted, to the extent required to cause the contents to flow from the container. To provide a generally uniform rate of discharge, which is the normal requirement, the tilt of the container has to be continually adjusted. This discharge method is labour and/or time intensive and is therefore not favoured.